Participants are expected to make their own hotel reservations. Some hotel lists are provided below, with typical prices, and distance to APC for hotels withing walking distance.
If you are staying a full week, renting an apartment as a group may be a better option. Appartments in the 5th, 6th, or 13th arrondissement (district) will be reasonably close to the workshop. Locations near metro line 14 or RER C will be most convenient for APC. Search google for "paris vacation rentals" to find sites like this: